As electronic business (e-business) grows, so does the need of better ways to share and manage large amounts of data. The amount of data storage required by today's e-businesses is staggering. Today almost all client access to large scale storage is accomplished by sending request through internet small computer system interface (iSCSI) based devices that connect an internet protocol (IP) network, example a local area network (LAN) or a wide area network (WAN), to storage network, example a storage area network (SAN).
However, serial attached SCSI (SAS) is an emerging industry standard as the enterprise-class standard storage interface. A typical SAS domain comprises SAS devices (e.g., host devices or initiators and target devices) interconnected with a set of point-to-point-links. For example, SAS can support up to 16,384 addressable devices in the SAS domain and point-to-point data transfer speeds up to 6 Gbit/s. In the SAS domain, the SAS devices use SAS commands for interacting with other SAS devices.
Another standard used for exchanging data between a host device and a target device using SCSI commands is iSCSI standard. iSCSI is a TCP/IP based protocol that carries the SCSI commands over an IP network to enable communication between iSCSI host and target devices. An advantage of iSCSI standard is that the iSCSI enables the iSCSI host and target devices to communicate with each other with no limitation to distance between them. Unlike the iSCSI, the SAS enables the SAS host and target devices to communicate with each other with limited operating distances. Currently, the SAS devices can span up to a range of about 6-7 meters. As a result, the SAS devices are mostly restricted to point-to-point connectivity and hence operate within limited operating distances.
Today, almost all backend storage devices are SAS devices or drives. The SAS devices are made part of the SAN through controllers which act as the SAN interface to the SAS devices. The SAS devices do not have any iSAN interface. Also currently, there are no SAS to iSCSI converters available for enabling the traffic between SAS devices and iSCSI devices.